Chia (Salvia hispanica L.) mucilage is a plant-based hydrocolloid that is receiving growing interest as a clean-label ingredient because it can bind water effectively, show pseudoplastic flow, form films and provide structure in foods without depending on conventional synthetic or highly processed binders. The mucilage is an extracellular polysaccharide released from the seed coat when the seeds are hydrated and consists of a heterogeneous mixture of soluble and insoluble polysaccharide fractions. Its functional characteristics are strongly affected by factors such as extraction temperature, hydration time, seed-to-water ratio, shear, drying and subsequent rehydration conditions. Conventional hydration remains a straightforward method for recovering the mucilage, while hot-water, ultrasound- and microwave-assisted methods can alter both extraction yield and the functional properties of the recovered material. In food formulations, chia mucilage has been explored for several purposes, including partial fat replacement in bakery products, phosphate reduction in emulsified meat products, thickening and stabilization of dairy-type systems, formation of edible films and coatings, and use as a carrier for emulsions and encapsulated ingredients. Studies have also shown that chia mucilage can act synergistically with commercial hydrocolloids, particularly in structured dairy products. Available evidence suggests that chia mucilage can provide several technological functions at the same time, which is valuable when developing clean-label foods. Nevertheless, differences in extraction procedures, colour, flavour, batch-to-batch performance, microbiological stability and the economics of scale-up remain important challenges. Future research should therefore give greater attention to standardized extraction procedures, structure-function relationships, processing stability, sensory optimization, techno-economic evaluation and validation under commercial food conditions. This review brings together information on the structural characteristics, extraction methods, functional properties and food applications of chia mucilage, with emphasis on its potential as a multifunctional natural binder and clean-label ingredient.